Conjunctivitis may be caused by bacteria, viruses, allergens, or irritants. What signs and symptoms differentiate bacterial conjunctivitis from other types

A. Subacute onset, severe pain, and preauricular adenopathy.
B. Recurrent onset, no pain, and clear discharge.
C. Acute onset, moderate pain, and purulent discharge.
D. Acute onset, mild pain, and clear discharg

（1）在化学实验课上，京京做粗盐提纯实验时，若想加快粗盐溶解，你建议他______．

（2）下图是氯化钠的溶解度曲线，观察曲线图，回答：

①a点所表示的是氯化钠溶液是______（填“饱和”或“不饱和”）溶液．

②若要从饱和的氯化钠溶液中得到大量的氯化钠晶体，应采用的方法是______（填“蒸发溶剂”或“冷却热饱和溶液”）．